Characterization of Fine Pitch CSP Solder Joints Under Board-Level Free Fall Drop (BFFD)

2005 ◽  
Author(s):  
Dongji Xie ◽  
David Geiger ◽  
Dongkai Shangguan ◽  
Daniel T. Rooney ◽  
Louis J. Gullo
Keyword(s):  
Failure Modes ◽  
Solder Joints ◽  
Cellular Phone ◽  
Free Fall ◽  
Drop Test ◽  
Strain Level ◽  
Board Structure ◽  
Element Analysis ◽  
Board Level ◽  
The Impact

This paper presented a board-level free fall drop (BFFD) to simulate product free fall drop (PFFD). In BFFD, the board structure is very close to the actual cellular phone boards with similar size. The board edges were reinforced by metal frame and screws similar to the cellular phone housing. The drop test was performed to characterize the solder joints of 0.4mm pitch chip scale package (CSP) packages. To charaterize the stress level, the acceleration was measured and the free drop test was performed for more than 140 boards with different CSP structures. The plastic strain of solder joints in different location was calculated using finite element analysis (FEA). It was found that the strain level is both location and component dependent. This strain level will determine the probability of drop test failure in terms of number of drops to failure. The impact of component type, body size and component location was investigated by both experimentally and FEA. Through drop test, the number of drop before failure (MDBF) were recorded and compared across various CSPs. Failure analysis was also performed to confirm the failure modes.

Experimental Evaluation on Solder Joint Reliability of PBGA Assembly Under Mechanical Drop Test

2002 ◽  
Author(s):  
Shi-Wei Ricky Lee ◽  
Yin-Lai Tracy Li ◽  
Hoi-Wai Ben Lui
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Solder Joints ◽  
Drop Test ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Free Solder ◽  
Board Level ◽  
Better Than ◽  
Mechanical Drop Test

The present study is intended to investigate the board level solder joint reliability of PBGA assemblies under mechanical drop test. During the course of this study, a five-leg experiment was designed to investigate various combinations of solder materials and peak reflow temperatures. Two major failure modes, namely, solder cracking and copper trace breakage, were identified. In addition, the critical location of solder joints was characterized. It was found that Sn-Pb eutectic solder joints performed better than Pb-free solder joints under mechanical impact loading.

Mechanical Event Simulation of Drop Testing for Toy Product

2006 ◽  
Vol 532-533 ◽  
pp. 993-996
Author(s):  
Anthony Yee Kai Yam ◽  
Kai Leung Yung ◽  
Chi Wo Lam
Keyword(s):  
Material Properties ◽  
Impact Analysis ◽  
Plastic Material ◽  
Free Fall ◽  
Drop Impact ◽  
Local Analysis ◽  
Element Analysis ◽  
Event Simulation ◽  
Long Time ◽  
The Impact

Toys that are free from drop failures normally take a long time to develop. It is often time and cost consuming after the production tooling is built to detect drop test failure. This paper introduces a new drop testing analysis method for Toys. The method uses a simple approach with a local analysis that based on the linear and non linear finite element analysis. Modeling and transient drop analysis of a pre-school toy is used as a case study to demonstrate the method. The impact analysis of the product hitting the solid concrete floor after a free fall is presented. The analysis focuses on the deformation of the housing for a product with electronic circuit and mechanical mechanism inside. Experimental data has been obtained for drop simulation of the housing and its correlation with the plastic material properties. The stress and strain of the housing during drop impact tests are noted. The effects of the material properties to the housing deflection under drop/impact shock have been investigated. Numerical results are compared with experimental results to validate the method.

Failure Analysis of Halogen-Free Printed Circuit Board Assembly Under Board-Level Drop Test

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Hung-Jen Chang ◽  
Chau-Jie Zhan ◽  
Tao-Chih Chang ◽  
Jung-Hua Chou
Keyword(s):  
Printed Circuit Board ◽  
Drop Test ◽  
Circuit Board ◽  
Printed Circuit Board Assembly ◽  
Printed Circuit ◽  
Plastic Ball ◽  
Circuit Board Assembly ◽  
Halogen Free ◽  
Board Level ◽  
The Impact

In this study, a lead-free dummy plastic ball grid array component with daisy-chains and Sn4.0Ag0.5Cu Pb-free solder balls was assembled on an halogen-free high density interconnection printed circuit board (PCB) by using Sn1.0Ag0.5Cu solder paste on the Cu pad surfaces of either organic solderable preservative (OSP) or electroless nickel immersion gold (ENIG). The assembly was tested for the effect of the formation extent of Ag3Sn intermetallic compound. Afterward a board-level pulse-controlled drop test was conducted on the as-reflowed assemblies according to the JESD22-B110 and JESD22-B111 standards, the impact performance of various surface finished halogen-free printed circuit board assembly was evaluated. The test results showed that most of the fractures occurred around the pad on the test board first. Then cracks propagated across the outer build-up layer. Finally, the inner copper trace was fractured due to the propagated cracks, resulting in the failure of the PCB side. Interfacial stresses numerically obtained by the transient stress responses supported the test observation as the simulated initial crack position was the same as that observed.

Dynamic Structural Analysis of the 9516 Transport Package

2010 ◽  
Author(s):  
Zenghu Han ◽  
Vikram N. Shah ◽  
Jeries Abou-Hanna ◽  
Yung Y. Liu
Keyword(s):  
Computer Code ◽  
General Purpose ◽  
Drop Test ◽  
Refined Model ◽  
Explicit Integration ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Containment Vessel ◽  
Bending Load ◽  
The Impact

This paper presents the structural dynamic analysis of the 9516 package subjected to two hypothetical accidents in sequence: (1) the 30-ft drop test and (2) the puncture test. The analysis is performed with the general-purpose finite element analysis computer code, ABAQUS, using explicit integration. The 9516 package consists of a containment vessel placed inside a cask mounted inside a steel cage, which acts as the impact limiter and the personnel shield. The cask has a bolted closure that provides the confinement to the containment vessel. The closure bolts initially were modeled with one-dimensional elastic connector elements bearing only the axial loads, which was adequate for the analysis of the drop test. However, the closure lid experienced significant bending during the puncture test, implying bending load acting on the closure bolts. Therefore, the closure bolts were modeled by using solid elements in a refined model so that the response to the bending load during the puncture test can be simulated. The results of the analysis showed that the closure bolts experience significant bending during the puncture test. For model validation, a comparison between the analysis results and the test results for rigid body accelerations of the package is presented. The results of the analysis based on the refined model show that the maximum stress intensities in the closure bolts, containment vessel, and cask are lower than the corresponding allowable stresses specified in the American Society of Mechanical Engineering Boiler and Pressure Vessel Code.

Influence of Impact Angle and Real Target Properties on Drop Test Results of Cubic Containers

2017 ◽  
Author(s):  
Uwe Zencker ◽  
Linan Qiao ◽  
Holger Völzke
Keyword(s):  
Free Fall ◽  
Impact Angle ◽  
Drop Test ◽  
Storage Site ◽  
Flat Bottom ◽  
Energy Agency ◽  
Accident Scenarios ◽  
Interim Storage ◽  
The Impact ◽  
Real Target

Drop test scenarios with cubic containers without impact limiters at interim storage sites or in a final repository have been investigated by numerical simulations. An ideally flat drop is impossible to conduct as a free fall of a container even under laboratory conditions. Dynamic stresses and strains inside the container structure are sensitive to the impact angle. Even very small impact angles cause remarkable changes in the experimental or numerical results when a flat bottom or wall of a container hits a flat target. For drop tests with transport packages the International Atomic Energy Agency (IAEA) regulations define an essentially unyielding target. In contrast, potential accident scenarios for storage containers are derived from site-specific safety analyses or acceptance criteria in Germany. Each interim storage site or repository has a yielding or so-called real target with individual structural and material properties. The real target acts as a kind of impact limiter. A more conservative container design is required if the impact limiting effect of the target is not considered.

Finite Element Analysis on the Blast Resistant Performance of Multibarrel Tube-Confined Concrete Column in Different Cross-Sections

2013 ◽  
Vol 721 ◽  
pp. 545-550
Author(s):  
Sai Wu ◽  
Jun Hai Zhao ◽  
Er Gang Xiong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Detonation Wave ◽  
Cross Section ◽  
Cross Sections ◽  
Failure Modes ◽  
Circular Cross Section ◽  
Blast Load ◽  
Element Analysis ◽  
The Impact

Based on the finite element analysis software ANSYS/LS-DYNA, this paper numerically analyzed the dynamic performance of MTCCCs with different cross sections under blast load, followed by the study and comparison on the differences of the detonation wave propagation and failure modes between the columns in circular cross section and square cross section. The results show: The blast resistant performance of the circular component is more superior than the square component for its better aerodynamic shape that can greatly reduce the impact of the detonation wave on the column; The main difference of the failure modes between the circular and square cross-sectional components under blast load lies in the different failure mode of the outer steel tube. The simulation results in this paper can provide some references for the blast resisting design of MTCCCs.

Stress Analysis of Printed Circuit Boards With Highly Populated Solder Joints and Components: A Micromechanics Approach

1996 ◽  
Vol 118 (2) ◽  
pp. 87-93
Author(s):  
K. X. Hu ◽  
Y. Huang ◽  
C. P. Yeh ◽  
K. W. Wyatt
Keyword(s):  
Stress Analysis ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Effective Properties ◽  
Mechanical Analysis ◽  
Computational Effort ◽  
Circuit Boards ◽  
Element Analysis ◽  
Printed Circuit ◽  
Board Level

The single most difficult aspect for thermo-mechanical analysis at the board level lies in to an accurate accounting for interactions among boards and small features such as solder joints and secondary components. It is the large number of small features populated in a close neighborhood that proliferates the computational intensity. This paper presents an approach to stress analysis for boards with highly populated small features (solder joints, for example). To this end, a generalized self-consistent method, utilizing an energy balance framework and a three-phase composite model, is developed to obtain the effective properties at board level. The stress distribution inside joints and components are obtained through a back substitution. The solutions presented are mostly in the closed-form and require a minimum computational effort. The results obtained by present approach are compared with those by finite element analysis. The numerical calculations show that the proposed micromechanics approach can provide reasonably accurate solutions for highly populated printed circuit boards.

Analysis on the Effect of Input Impact Profiles in Drop Test

2007 ◽  
Author(s):  
Jiang Zhou ◽  
Ratna P. Niraula ◽  
Kendrick Aung
Keyword(s):  
Dynamic Response ◽  
Impact Load ◽  
Block Diagram ◽  
Input Pulse ◽  
Drop Test ◽  
System Level ◽  
System Response ◽  
Time Duration ◽  
Board Level ◽  
The Impact

The objective of this paper is to develop an analytical or mathematical predicative model for the evaluation of dynamic response of a structural element in a microelectronic or an optoelectronic product to an impact load occurring as a result of drop or shock test. Closed-form theoretical solution was obtained to simulate the board level drop test. The block diagram based SIMULINK analysis was introduced to determine the response with various impact configurations for the system level drop test as well. This study will help reliability engineers to design the impact input profiles and obtain the desired responses, and to calibrate and validate finite element analysis results quickly for both board level and system level drop test. It was found that time durations of the input profiles play an important role in the dynamic response. The system response can be designed by carefully choosing the impact time duration. Certain input pulse time results in the response with very low ringing after first or second peaks.

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